General (Effects of Adoption ASU 2018-12, Segment Results) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022		Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net incurred claims and benefits (1)	$ 1,646	$ 1,472
Core income (loss) before income tax	406	366
Income tax (expense) benefit on core income (loss)	(81)	(68)
Core income (loss)	325	298
Claim and claim adjustment expenses	22,409		$ 22,120	[1]
Future policy benefits	13,976	16,002	13,480	[1]	$ 19,132
Life & Group | Operating Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net incurred claims and benefits (1)	311	304
Core income (loss) before income tax	(12)	(7)
Income tax (expense) benefit on core income (loss)	9	12
Core income (loss)	(3)	5
Claim and claim adjustment expenses	704		695
Future policy benefits	$ 13,976		13,480
Prior to Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Claim and claim adjustment expenses			25,099
Future policy benefits			10,151		$ 13,318
Prior to Adoption | Life & Group | Operating Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net incurred claims and benefits (1)		281
Core income (loss) before income tax		16
Income tax (expense) benefit on core income (loss)		7
Core income (loss)		23
Claim and claim adjustment expenses			3,674
Future policy benefits			10,151
Effect of Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Claim and claim adjustment expenses			(2,979)
Future policy benefits			3,329
Effect of Adoption | Life & Group | Operating Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net incurred claims and benefits (1)		23
Core income (loss) before income tax		(23)
Income tax (expense) benefit on core income (loss)		5
Core income (loss)		$ (18)
Claim and claim adjustment expenses			(2,979)
Future policy benefits			$ 3,329

[1] As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Condensed Consolidated Financial Statements for additional information.